1. Field of the Invention
This invention pertains to hand operated calculators. More particularly, this invention pertains to a calculator for use in calculating a length of a patch cord necessary to extend between two locations in an optical fiber distribution bay.
2. Description of the Prior Art
The increased use of optical fiber transmission in the telecommunications industry has resulted in a need for the development of optical fiber termination equipment. An example of such equipment is found in commonly assigned and co-pending U.S. patent application Ser. No. 07/388,060 filed July 31, 1989 which discloses an optical fiber distribution frame. A plurality of distribution frames (i.e., a bay) are shown in side-by-side relation. Each of the frames includes a vertical array of modular cabinets which may include an optical fiber connector module. Disposed between the sides of each of the frames are vertical pathways for optical fiber cables. Also, troughs are provided along the bottom edge of each of the frames. The troughs of adjacent frames are aligned to define a horizontal cable pathway which is in communication with the vertical cable pathways.
In the aforementioned application, when it is desirable to connect a connector module of one frame with a connector module of another frame, an optical fiber patch cord is used. The patch cord has one end connected to the first optical fiber connector module (the "originating module") and the patch cord is then extended down the vertical pathway until it reaches the horizontal trough. The patch cord is then extended horizontally along the horizontal trough until it is fed vertically up the vertical pathway near the other module (the "terminating module"). Accordingly, the length of patch cord necessary to connect an originating and a terminating connector module has a length which is the subject of several variables including: the vertical location of the originating module, the vertical location of the terminating module, and the horizontal distance between the frames which contain two modules.
Commercially available optical fiber patch cord is commonly provided by manufacturers and distributors in fixed lengths. For example, ADC Telecommunications, Inc., Minneapolis, MN (assignee of the present invention) provides patch cords (designated "T-Series") of various predetermined lengths. These could include 115 inches, 123 inches, 131 inches and 139 inches (referred to as 11T, 12T, 13T and 14T, respectively).
It is desirable to provide a quick and ready way for a user of a patch cord to calculate the optimum length of patch cord necessary to extend between an originating and terminating connector module where the vertical locations of the modules and the numbers of troughs separating the frames carrying the two modules is variable. Such is an object of the present invention.